1508 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1953 



width was essentially constant and independent of the particular vowel. The 

 mean values for bars 1, 2, and 3 were 130, 100, and 185 cps, respectively. Ten 

 per cent of the 300 band widths measured were less than 90 cps and ten per 

 cent greater than 260 cps. 



Brangaccio, D. J., see C. C. Cutler. 



Brattain, W. H., see A. M. Portis. 



BULLINGTON, K.^ 



Frequency Economy in Mobile Radio Bands, I.R.E., Trans., P.G.V.C., 

 3, pp. 4-27, June, 1953 (Monograph 2109). 



Calbick, C. J., see D. A. McLean. 



Campbell, R. D.^ 



Path Testing for Microwave Radio Routes, Elec. Eng., 72, pp. 571- 

 577, July, 1953. 



Campbell, W. E.^ 



Solid Lubricants, Lubrication Eng., 9, pp. 195-200, Aug., 1953. 



CiCCOLELLA, D. F.^ AND L. J. LaBRIE^ 



High Frequency Crystal Units for Use in Selective Networks and 

 Their Proposed Application in Filters Suitable for Mobile Radio 

 Channel Selection, I.R.E., Trans, P.G.V.C. 3, pp. 118-128, June, 1953. 



Conwell, E. M.^ 



High Field Mobility in Germanium With Impurity Scattering Domi- 

 nant, Phys. Rev., 90, pp. 769-772, June 1, 1953. 



Experimental measurements show a variation of mobility with electric field 

 intensity of electrons in n type germanium which differs at 20 degrees K from 

 that observed in the same specimen at 77 degrees K and higher temperatures. 

 This difference can be accounted for by scattering by ionized impurities. A 

 crude quantitative treatment is carried out along the lines of Shockley's 

 treatment for the case of lattice scattering. As in that case, the resulting 

 theory fits the data well if the rate of energy loss is taken several times higher 

 than that given by the theory assuming that the surfaces of constant energy 

 are spherical. 



1 Bell Telephone Laboratories, Inc. 



2 American Telephone and Telegraph Company. 

 ^ Formerly Hell Toloi)h()nc Laboratories. 



